Filtration is a common method of separating larger particles in solution from smaller ones. Filters, filtrations devices and filtration methods are used in a wide range of biological and chemical applications for the separation or purification of various moieties.
Syringe filters are used in the art to filter liquids. Such filters are regularly used for the lab-scale filtration of liquids. The use of such filters typically comprises drawing the sample to be filtered into a syringe. The syringe is then attached to a syringe filter and the liquid is then pushed through the filter. Since the syringe and the filter are separate components that are brought together by the end user, filter manufactures cannot control the quality of the syringes that customers use. In some circumstances, use of the wrong syringe can result in leachables from the syringe entering the filtrate.
Often, when extracting a sample that requires filtration it is necessary to filter a volume of liquid larger than the volume of the syringe. In such circumstances, once the user has pushed the liquid from the syringe through the filter, the user would then have to remove the filter in order to draw up more of the (unfiltered) liquid sample into the syringe. The filter would then need to be replaced for the dispensing stage to ensure that the sample liquid is filtered. This process would need to be repeated until the full volume of liquid sample has been filtered. This can be time consuming and burdensome for the user. Furthermore, the need to move the syringe between filtration steps and to remove and re-attach the filter increases the risk of contamination of the solution to be filtered.
It would be desirable to provide a filtration device that permits the user to draw in and filter a solution without having to change or remove the filter to refill the syringe. GE Healthcare have commercialised a filtration device, a Clyde in-line filter, through its Whatman™ portfolio. The Clyde™ device is a single device system comprising a sample inlet pipe, a one-way valve, a flat filter, a syringe and connecting pipework. The device permits a user to filter up to 2 L of solution in a continuous process. The device can be built with a limited number of available filters.
However, there is a continuing need in the art to provide alternative forms of “one way” filters that can be manufactured on a large scale from readily available, cost-effective materials and which are simple and easy to operate by a user—typically a lab researcher or technician.